DEVELOPMENT OF HIGH PERFORMANCE Fe-B/Nd_2Fe_(14)B BASED NANOCOMPOSITE HARD MAGNET FOR STRIP CASTING PROCESS

摘要

Effects of Ti and C on composition of Nd content from 6 to 9 atomic percent and B content from 10 to 15 atomic percent have been investigated. It is found that Ti addition promotes formation of Nd_2Fe_(14)B and partial substitution of C for B refines microstructure. High coercivity Fe-B/Nd_2Fe_(14)B based nanocomposite magnet powder 'SPRAX-II' mass-producible by means of strip casting process has been developed making use of the Ti-C addition. SPRAX-II has the excellent thermal stability and oxidation resistance compared with conventional melt-spun Nd-Fe-B magnets. Excellent magnetic properties of B_r = 0.913 T, H_(cJ) = 767.5 kA/m, (BH)_(max) = 123.5 kJ/m~3 are obtained in the laboratory-scale strip-cast alloys after a heat treatment.